铍材表层应力梯度对X射线应力测试的影响

Effect of Stress Gradients near the Surface Beryllium on the X-ray Stress Measurement

研究了在 modified-ψ衍射几何条件下 ,铍材表层中存在不同应力梯度时的 d～ sin2 ψ曲线的形状 ,确定了铍材表层内的应力梯度对常规的 X射线应力测试的影响。结果表明 :在通常的 sin2 ψ≤ 0 . 5的应力测试范围内 ,应力梯度对测试曲线有明显的影响 ,应力测试值因应力梯度的存在而偏离真实值 ;选择合适的靶材以减小 X射线对铍材的穿透深度 ,可以减小应力测试的误差。

The shape of d vs sin 2 ψ curve with stress gradient near the beryllium surface is studied under the modified ψ diffraction geometry condition, and the effect of stress gradient near the beryllium surface on the conventional x ray stress measurement is determined. The result shows that when sin 2 ψ ≤0.5,stress gradient has significant effects on the measured curve, which shifts the real value for the presence of stress gradient. The error of stress measurement can be decreased by selecting proper target to decrease the penetrate depth of x ray into beryllium.